Iron, protein and the mistakes new plant-based athletes make

Athletes who change how they eat generally get the training right and the nutrition adjustment wrong in predictable ways.

Mistake one: not eating enough

Covered at length elsewhere on this site and it belongs at the top of every list.

Plant foods are less energy dense. An athlete who substitutes without increasing volume or density ends up in a deficit.

The symptoms — fatigue, plateauing performance, feeling cold, poor recovery, disturbed sleep, in women menstrual changes — get attributed to the diet being inadequate when the diet is simply too small.

The fix: track intake honestly for four days including a weekend. Most people find a gap of several hundred calories.

Mistake two: too much fibre before training

Baseline fibre intake goes up substantially, which is generally good and is a problem immediately before hard sessions.

Gastrointestinal distress during training is common in the first months and it is nearly always this.

The fix: lower fibre in the hours before training. White rice, white bread, peeled potatoes, a banana, a sports drink.

Wholegrain everything, all the time, is not the goal for an athlete. Save the fibre for meals away from training.

Mistake three: protein as an afterthought

Not the total — the distribution.

Athletes frequently get most of their protein at dinner, with breakfast and lunch contributing very little.

The evidence supports spreading it across four or five feedings with a meaningful amount in each.

The fix: a protein source at every eating occasion. Soy milk rather than other plant milks at breakfast. Legumes or tofu at lunch. A recovery drink after training.

Mistake four: ignoring iron until symptomatic

Iron requirements are higher in endurance athletes, and higher again in menstruating women. Plant iron is less well absorbed.

Deficiency develops slowly and presents as fatigue and declining performance, which athletes attribute to training load.

The fix: get tested. Full blood count and ferritin, before symptoms.

Then manage absorption: vitamin C with iron-containing meals, tea and coffee away from meals, and legumes soaked and well cooked.

Do not supplement without testing.

Mistake five: forgetting creatine

Creatine is found almost exclusively in animal foods. Vegetarians and vegans have lower muscle creatine stores.

Studies consistently find that plant-based individuals show larger responses to supplementation than omnivores, presumably because they start lower.

For anyone doing high-intensity or resistance work, this is among the best-evidenced supplements available, it is cheap, and it is one of the few genuinely worth taking.

Three to five grams a day of creatine monohydrate. Vegan-suitable products are widely available.

Mistake six: B12 and omega-3 not addressed

B12 is non-negotiable and it is frequently postponed.

Long-chain omega-3 is poorly supplied, and an algal supplement addresses it directly.

Neither is expensive and neither should be left until a year in.

Mistake seven: too much fibre around competition

Related to the training point and worth stating separately.

The day before an event is not the time to eat a large bowl of beans and brassicas.

Reduce fibre for twenty-four to forty-eight hours before a key event, use familiar foods, and practise the plan in training rather than experimenting on the day.

Mistake eight: over-relying on processed alternatives

Meat substitutes are convenient and frequently high in salt and low in fibre and micronutrients relative to whole legumes.

Nothing wrong with them as part of a diet. Building a diet on them misses most of the benefit.

Whole legumes, soy foods, grains, nuts and vegetables should be the base.

Mistake nine: fat phobia

Athletes who are trying to eat healthily frequently reduce fat, which is precisely the wrong direction when energy density is the constraint.

Fat is the most efficient lever for adding energy without adding volume, and it carries fat-soluble vitamins.

Olive oil, nuts, tahini, avocado. Use them.

Mistake ten: changing everything at once

Changing diet during a heavy training block or close to a competition is a poor plan.

Transition during a lower-volume period, allow several weeks for gut adaptation, and do not test a new fuelling strategy on race day.

The things that are not problems

Worth stating for balance.

Protein quality, provided total intake is adequate and sources are varied. Athletes on plant-based diets meeting their targets do not show impaired adaptation in the available research.

Performance generally. Studies comparing athletes on plant-based and mixed diets have not found consistent performance disadvantages when energy and nutrient intake are adequate.

The gains claimed for plant-based diets in athletic performance are also frequently overstated. The honest position is that it can be done well, and that doing it badly causes the problems above.

General information rather than individual advice. Athletes should work with a sports dietitian, particularly during a transition. Do not supplement iron without testing.